Thio compounds

ABSTRACT

A compound, or a pharmaceutically acceptable salt or ester thereof, having a structure of: 
                         
wherein A, B and D are each oxygen or sulfur, provided that least one of A, B and D is sulfur; and R 1 -R 8  are each independently hydrogen, hydroxyl, acyl, substituted acyl, acyloxy, substituted acyloxy, alkyl, substituted alkyl, alkenyl, substituted alkenyl, alkynyl, substituted alkynyl, alkoxy, substituted alkoxy, aryl, substituted aryl, amino, substituted amino, halogen, heterocycloalkyl, substituted heterocycloalkyl, heteroaryl, substituted heteroaryl, or a thio-containing group.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No.14/746,512, filed Jun. 22, 2015, now issued as U.S. Pat. No. 9,623,020,which is a continuation of U.S. application Ser. No. 14/571,138, filedDec. 15, 2014, now issued as U.S. Pat. No. 9,084,783, which is adivisional of U.S. application Ser. No. 13/310,242, filed Dec. 2, 2011,now issued as U.S. Pat. No. 8,927,725, each of which is incorporated byreference herein in its entirety.

BACKGROUND

Thalidomide (N-α-phthalimidoglutarimide) is a glutamic acid derivativethat was introduced onto the market as a sedative hypnotic in 1956, butwas withdrawn in 1961 due to the development of severe congenitalabnormalities in babies born to mothers using it for morning sickness.Interest in the agent was reawakened after thalidomide was foundclinically effective in the treatment of erythema nodosum leprosum (ENL)and in the treatment of HIV wasting syndrome and various cancers.Mechanistic studies of its ENL activity demonstrated an anti-tumornecrosis factor alpha (anti-TNF-α) action. Specifically, thalidomideenhances the degradation of TNF-αRNA, and thereby lowers its synthesisand secretion. Further studies have defined it to be a co-stimulator ofboth CD8+ and CD4+ T cells, an inhibitor of angiogenesis via itsinhibitory actions on basic fibroblast growth factor (bFGF) and vascularendothelial growth factor (VEGF), and an inhibitor of the transcriptionfactor, NFκB.

TNF-α and family members play pivotal roles in a variety ofphysiological and pathological processes, which include cellproliferation and differentiation, apoptosis, the modulation of immuneresponses and induction of inflammation. TNF-α acts via two receptors,TNFR1 and 2. The former is expressed in all tissues and is thepredominant signaling receptor for TNF-α. The latter is primarilyexpressed on immune cells and mediates more limited biologicalresponses. The exposure of cells to TNF-α can result in activation of acaspase cascade leading to cell death via apoptosis. Indeed, major cellsurface molecules capable of initiating apoptosis are members of the TNFfamily of ligands and receptors. For example, death-inducing members ofthe TNF receptor family each contain a cytoplasmic ‘death domain’ (DD),which is a protein-protein interaction motif critical for engagingdownstream components of the signal transduction machinery.

Recently, TRAIL, the tumor necrosis factor-related apoptosis-inducingligand, has been shown to selectively induce apoptosis of tumor cells,but not most normal cells. It is indicated that TRAIL mediates thymocyteapoptosis and is important in the induction of autoimmune diseases. Moreoften, however, TNF-α receptor binding induces the activation oftranscription factors, AP-1 and NFκB, that thereafter induce genesinvolved in acute and chronic inflammatory responses. Overproduction ofTNF-α has thus been implicated in many inflammatory diseases, such asrheumatoid arthritis, graft-versus-host disease and Crohn's disease, andit additionally exacerbates ENL, septic shock, AIDS and dementiaassociated with Alzheimer's disease (AD).

SUMMARY

Disclosed herein is a compound, or a pharmaceutically acceptable salt orester thereof, having a structure of:

wherein A, B and D are each oxygen or sulfur, provided that least one ofA, B and D is sulfur; and R¹-R⁸ are each independently hydrogen,hydroxyl, acyl, substituted acyl, acyloxy, substituted acyloxy, alkyl,substituted alkyl, alkenyl, substituted alkenyl, alkynyl, substitutedalkynyl, alkoxy, substituted alkoxy, aryl, substituted aryl, amino,substituted amino, halogen, heterocycloalkyl, substitutedheterocycloalkyl, heteroaryl, substituted heteroaryl, or athio-containing group.

Also disclosed herein a compound, or a pharmaceutically acceptable saltor ester, thereof, having a structure of:

wherein A, B, D and E are each oxygen or sulfur, provided that least oneof A, B, D and E is sulfur; and R²-R⁴ and R⁶-R⁸ are each independentlyhydrogen, hydroxyl, acyl, substituted acyl, acyloxy, substitutedacyloxy, alkyl, substituted alkyl, alkenyl, substituted alkenyl,alkynyl, substituted alkynyl, alkoxy, substituted alkoxy, aryl,substituted aryl, amino, substituted amino, halogen, heterocycloalkyl,substituted heterocycloalkyl, heteroaryl, substituted heteroaryl, or athio-containing group.

These compounds may be used for treating, for example, aneurodegenerative disorder or an autoimmune disease.

The foregoing and will become more apparent from the following detaileddescription, which proceeds with reference to the accompanying figures.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a graph depicting data on cellular health assessed by an LDHassay.

FIG. 2 is a graph depicting data on TNF-α protein levels.

FIGS. 3 and 4 are graphs depicting data on cellular health assessed byan MTS assay.

FIGS. 5A-5C. Concentration-dependence of effects of certain compounds onhuman T cell generation of cytokines. Each column and bar depicts themean±S.D. of the results of cytokine ELISAs of supernates from T cellsof a total of four healthy subjects, of whom two were young and two wereold, after three days of incubation with anti-CD3+ anti-CD28 antibodieswithout (control=100%) and with a drug. The mean±S.D. of control (100%)values for IFN-γ, IL-2 and IL-17, respectively, where 30,915±11,206,5.8±3.4 and 1149±372 pg/ml. A=IFN-γ, B=IL-2 and C=IL-17. Statisticalsignificance of differences from the controls without an IMD wascalculated by a two-sample t test and indicated by + for p<0.05,*forp<0.01 and**for p<0.001.

DETAILED DESCRIPTION I. Abbreviations

TNF-α—tumor necrosis factor alpha

CDI—carboxyamidotriazole

ARE—adenylate/uridylate (AU)-rich element

UTR—untranslated region

THF—tetrahydrofuran

NMR—nuclear magnetic resonance

LR—Lawesson's Reagent

II. Terms

In order to facilitate an understanding of the embodiments presented,the following explanations are provided.

The singular terms “a,” “an,” and “the” include plural referents unlesscontext clearly indicates otherwise. Similarly, the word “or” isintended to include “and” unless the context clearly indicatesotherwise. The term “comprises” means “includes.” Also, “comprising A orB” means including A or B, or A and B, unless the context clearlyindicates otherwise. It is to be further understood that all molecularweight or molecular mass values given for compounds are approximate, andare provided for description. Although methods and materials similar orequivalent to those described herein can be used in the practice ortesting of this disclosure, suitable methods and materials are describedbelow. In addition, the materials, methods, and examples areillustrative only and not intended to be limiting.

“Administration of” and “administering a” compound or agent should beunderstood to mean providing a compound or agent, a prodrug of acompound or agent, or a pharmaceutical composition as described herein.The compound, agent or composition can be administered by another personto the subject (e.g., intravenously) or it can be self-administered bythe subject (e.g., tablets).

The term “subject” refers to animals, including mammals (for example,humans and veterinary animals such as dogs, cats, pigs, horses, sheep,and cattle).

An “R-group” or “substituent” refers to a single atom (for example, ahalogen atom) or a group of two or more atoms that are covalently bondedto each other, which are covalently bonded to an atom or atoms in amolecule to satisfy the valency requirements of the atom or atoms of themolecule, typically in place of a hydrogen atom. Examples ofR-groups/substituents include alkyl groups, hydroxyl groups, alkoxygroups, acyloxy groups, mercapto groups, and aryl groups.

“Substituted” or “substitution” refer to replacement of a hydrogen atomof a molecule or an R-group with one or more additional R-groups such ashalogen, alkyl, alkoxy, alkylthio, trifluoromethyl, acyloxy, hydroxy,mercapto, carboxy, aryloxy, aryl, arylalkyl, heteroaryl, amino,alkylamino, dialkylamino, morpholino, piperidino, pyrrolidin-1-yl,piperazin-1-yl, nitro, sulfato or other R-groups.

“Acyl” refers to a group having the structure RCO—, where R may bealkyl, or substituted alkyl. “Lower acyl” groups are those that containone to six carbon atoms.

“Acyloxy refers to a group having the structure RCOO—, where R may bealkyl or substituted alkyl. “Lower acyloxy” groups contain one to sixcarbon atoms.

“Alkenyl” refers to a cyclic, branched or straight chain groupcontaining only carbon and hydrogen, and unless otherwise mentionedtypically contains one to twelve carbon atoms, and contains one or moredouble bonds that may or may not be conjugated. Alkenyl groups may beunsubstituted or substituted. “Lower alkenyl” groups contain one to sixcarbon atoms.

The term “alkoxy” refers to a straight, branched or cyclic hydrocarbonconfiguration and combinations thereof, including from 1 to 20 carbonatoms, preferably from 1 to 8 carbon atoms (referred to as a “loweralkoxy”), more preferably from 1 to 4 carbon atoms, that include anoxygen atom at the point of attachment. An example of an “alkoxy group”is represented by the formula —OR, where R can be an alkyl group,optionally substituted with an alkenyl, alkynyl, aryl, aralkyl,cycloalkyl, halogenated alkyl, alkoxy or heterocycloalkyl group.Suitable alkoxy groups include methoxy, ethoxy, n-propoxy, i-propoxy,n-butoxy, i-butoxy, sec-butoxy, tert-butoxy cyclopropoxy, cyclohexyloxy,and the like.

The term “alkyl” refers to a branched or unbranched saturatedhydrocarbon group of 1 to 24 carbon atoms, such as methyl, ethyl,n-propyl, isopropyl, n-butyl, isobutyl, t-butyl, pentyl, hexyl, heptyl,octyl, decyl, tetradecyl, hexadecyl, eicosyl, tetracosyl and the like. A“lower alkyl” group is a saturated branched or unbranched hydrocarbonhaving from 1 to 6 carbon atoms. Preferred alkyl groups have 1 to 4carbon atoms. Alkyl groups may be “substituted alkyls” wherein one ormore hydrogen atoms are substituted with a substituent such as halogen,cycloalkyl, alkoxy, amino, hydroxyl, aryl, alkenyl, or carboxyl. Forexample, a lower alkyl or (C₁-C₆)alkyl can be methyl, ethyl, propyl,isopropyl, butyl, iso-butyl, sec-butyl, pentyl, 3-pentyl, or hexyl;(C₃-C₆)cycloalkyl can be cyclopropyl, cyclobutyl, cyclopentyl, orcyclohexyl; (C₃-C₆)cycloalkyl(C₁-C₆)alkyl can be cyclopropylmethyl,cyclobutylmethyl, cyclopentylmethyl, cyclohexylmethyl,2-cyclopropylethyl, 2-cyclobutylethyl, 2-cyclopentylethyl, or2-cyclohexylethyl; (C₁-C₆)alkoxy can be methoxy, ethoxy, propoxy,isopropoxy, butoxy, iso-butoxy, sec-butoxy, pentoxy, 3-pentoxy, orhexyloxy; (C₂-C₆)alkenyl can be vinyl, allyl, 1-propenyl, 2-propenyl,1-butenyl, 2-butenyl, 3-butenyl, 1-pentenyl, 2-pentenyl, 3-pentenyl,4-pentenyl, 1-hexenyl, 2-hexenyl, 3-hexenyl, 4-hexenyl, or 5-hexenyl;(C₂-C₆)alkynyl can be ethynyl, 1-propynyl, 2-propynyl, 1-butynyl,2-butynyl, 3-butynyl, 1-pentynyl, 2-pentynyl, 3-pentynyl, 4-pentynyl,1-hexynyl, 2-hexynyl, 3-hexynyl, 4-hexynyl, or 5-hexynyl;(C₁-C₆)alkanoyl can be acetyl, propanoyl or butanoyl; halo(C₁-C₆)alkylcan be iodomethyl, bromomethyl, chloromethyl, fluoromethyl,trifluoromethyl, 2-chloroethyl, 2-fluoroethyl, 2,2,2-trifluoroethyl, orpentafluoroethyl; hydroxy(C₁-C₆)alkyl can be hydroxymethyl,1-hydroxyethyl, 2-hydroxyethyl, 1-hydroxypropyl, 2-hydroxypropyl,3-hydroxypropyl, 1-hydroxybutyl, 4-hydroxybutyl, 1-hydroxypentyl,5-hydroxypentyl, 1-hydroxyhexyl, or 6-hydroxyhexyl;(C₁-C₆)alkoxycarbonyl can be methoxycarbonyl, ethoxycarbonyl,propoxycarbonyl, isopropoxycarbonyl, butoxycarbonyl, pentoxycarbonyl, orhexyloxycarbonyl; (C₁-C₆)alkylthio can be methylthio, ethylthio,propylthio, isopropylthio, butylthio, isobutylthio, pentylthio, orhexylthio; (C₂-C₆)alkanoyloxy can be acetoxy, propanoyloxy, butanoyloxy,isobutanoyloxy, pentanoyloxy, or hexanoyloxy.

“Alkynyl” refers to a cyclic, branched or straight chain groupcontaining only carbon and hydrogen, and unless otherwise mentionedtypically contains one to twelve carbon atoms, and contains one or moretriple bonds. Alkynyl groups may be unsubstituted or substituted. “Loweralkynyl” groups are those that contain one to six carbon atoms.

The term “halogen” refers to fluoro, bromo, chloro and iodosubstituents.

“Aryl” refers to a monovalent unsaturated aromatic carbocyclic grouphaving a single ring (e.g., phenyl) or multiple condensed rings (e.g.,naphthyl or anthryl), which can optionally be unsubstituted orsubstituted.

The term “amino” refers to an R-group having the structure —NH₂, whichcan be optionally substituted with, for example, lower alkyl groups, toyield an amino group having the general structure —NHR or —NR₂.

“Nitro” refers to an R-group having the structure —NO₂.

The term “aliphatic” as applied to cyclic groups refers to ringstructures in which any double bonds that are present in the ring arenot conjugated around the entire ring structure.

The term “aromatic” as applied to cyclic groups refers to ringstructures which contain double bonds that are conjugated around theentire ring structure, possibly through a heteroatom such as an oxygenatom or a nitrogen atom. Aryl groups, pyridyl groups and furan groupsare examples of aromatic groups. The conjugated system of an aromaticgroup contains a characteristic number of electrons, for example, 6 or10 electrons that occupy the electronic orbitals making up theconjugated system, which are typically un-hybridized p-orbitals.

“Pharmaceutical compositions” are compositions that include an amount(for example, a unit dosage) of one or more of the disclosed compoundstogether with one or more non-toxic pharmaceutically acceptableadditives, including carriers, diluents, and/or adjuvants, andoptionally other biologically active ingredients. Such pharmaceuticalcompositions can be prepared by standard pharmaceutical formulationtechniques such as those disclosed in Remington's PharmaceuticalSciences, Mack Publishing Co., Easton, Pa. (19th Edition).

The terms “pharmaceutically acceptable salt or ester” refers to salts oresters prepared by conventional means that include salts, e.g., ofinorganic and organic acids, including but not limited to hydrochloricacid, hydrobromic acid, sulfuric acid, phosphoric acid, methanesulfonicacid, ethanesulfonic acid, malic acid, acetic acid, oxalic acid,tartaric acid, citric acid, lactic acid, fumaric acid, succinic acid,maleic acid, salicylic acid, benzoic acid, phenylacetic acid, mandelicacid and the like. “Pharmaceutically acceptable salts” of the presentlydisclosed compounds also include those formed from cations such assodium, potassium, aluminum, calcium, lithium, magnesium, zinc, and frombases such as ammonia, ethylenediamine, N-methyl-glutamine, lysine,arginine, ornithine, choline, N,N′-dibenzylethylenediamine,chloroprocaine, diethanolamine, procaine, N-benzylphenethylamine,diethylamine, piperazine, tris(hydroxymethyl)aminomethane, andtetramethylammonium hydroxide. These salts may be prepared by standardprocedures, for example by reacting the free acid with a suitableorganic or inorganic base. Any chemical compound recited in thisspecification may alternatively be administered as a pharmaceuticallyacceptable salt thereof. “Pharmaceutically acceptable salts” are alsoinclusive of the free acid, base, and zwitterionic forms. Descriptionsof suitable pharmaceutically acceptable salts can be found in Handbookof Pharmaceutical Salts, Properties, Selection and Use, Wiley VCH(2002). When compounds disclosed herein include an acidic function suchas a carboxy group, then suitable pharmaceutically acceptable cationpairs for the carboxy group are well known to those skilled in the artand include alkaline, alkaline earth, ammonium, quaternary ammoniumcations and the like. Such salts are known to those of skill in the art.For additional examples of “pharmacologically acceptable salts,” seeBerge et al., J. Pharm. Sci. 66:1 (1977).

“Pharmaceutically acceptable esters” includes those derived fromcompounds described herein that are modified to include a carboxylgroup. An in vivo hydrolysable ester is an ester, which is hydrolysed inthe human or animal body to produce the parent acid or alcohol.Representative esters thus include carboxylic acid esters in which thenon-carbonyl moiety of the carboxylic acid portion of the ester groupingis selected from straight or branched chain alkyl (for example, methyl,n-propyl, t-butyl, or n-butyl), cycloalkyl, alkoxyalkyl (for example,methoxymethyl), aralkyl (for example benzyl), aryloxyalkyl (for example,phenoxymethyl), aryl (for example, phenyl, optionally substituted by,for example, halogen, C.sub.1-4 alkyl, or C.sub.1-4 alkoxy) or amino);sulphonate esters, such as alkyl- or aralkylsulphonyl (for example,methanesulphonyl); or amino acid esters (for example, L-valyl orL-isoleucyl). A “pharmaceutically acceptable ester” also includesinorganic esters such as mono-, di-, or tri-phosphate esters. In suchesters, unless otherwise specified, any alkyl moiety presentadvantageously contains from 1 to 18 carbon atoms, particularly from 1to 6 carbon atoms, more particularly from 1 to 4 carbon atoms. Anycycloalkyl moiety present in such esters advantageously contains from 3to 6 carbon atoms. Any aryl moiety present in such esters advantageouslycomprises a phenyl group, optionally substituted as shown in thedefinition of carbocycylyl above. Pharmaceutically acceptable estersthus include C₁-C₂₂ fatty acid esters, such as acetyl, t-butyl or longchain straight or branched unsaturated or omega-6 monounsaturated fattyacids such as palmoyl, stearoyl and the like. Alternative aryl orheteroaryl esters include benzoyl, pyridylmethyloyl and the like any ofwhich may be substituted, as defined in carbocyclyl above. Additionalpharmaceutically acceptable esters include aliphatic L-amino acid esterssuch as leucyl, isoleucyl and especially valyl.

For therapeutic use, salts of the compounds are those wherein thecounter-ion is pharmaceutically acceptable. However, salts of acids andbases which are non-pharmaceutically acceptable may also find use, forexample, in the preparation or purification of a pharmaceuticallyacceptable compound.

The pharmaceutically acceptable acid and base addition salts asmentioned hereinabove are meant to comprise the therapeutically activenon-toxic acid and base addition salt forms which the compounds are ableto form. The pharmaceutically acceptable acid addition salts canconveniently be obtained by treating the base form with such appropriateacid. Appropriate acids comprise, for example, inorganic acids such ashydrohalic acids, e.g. hydrochloric or hydrobromic acid, sulfuric,nitric, phosphoric and the like acids; or organic acids such as, forexample, acetic, propanoic, hydroxyacetic, lactic, pyruvic, oxalic (i.e.ethanedioic), malonic, succinic (i.e. butanedioic acid), maleic,fumaric, malic (i.e. hydroxybutanedioic acid), tartaric, citric,methanesulfonic, ethanesulfonic, benzenesulfonic, p-toluenesulfonic,cyclamic, salicylic, p-aminosalicylic, pamoic and the like acids.Conversely said salt forms can be converted by treatment with anappropriate base into the free base form.

The compounds containing an acidic proton may also be converted intotheir non-toxic metal or amine addition salt forms by treatment withappropriate organic and inorganic bases. Appropriate base salt formscomprise, for example, the ammonium salts, the alkali and earth alkalinemetal salts, e.g. the lithium, sodium, potassium, magnesium, calciumsalts and the like, salts with organic bases, e.g. the benzathine,N-methyl-D-glucamine, hydrabamine salts, and salts with amino acids suchas, for example, arginine, lysine and the like.

The term “addition salt” as used hereinabove also comprises the solvateswhich the compounds described herein are able to form. Such solvates arefor example hydrates, alcoholates and the like.

The term “quaternary amine” as used hereinbefore defines the quaternaryammonium salts which the compounds are able to form by reaction betweena basic nitrogen of a compound and an appropriate quaternizing agent,such as, for example, an optionally substituted alkylhalide, arylhalideor arylalkylhalide, e.g. methyliodide or benzyliodide. Other reactantswith good leaving groups may also be used, such as alkyltrifluoromethanesulfonates, alkyl methanesulfonates, and alkylp-toluenesulfonates. A quaternary amine has a positively chargednitrogen. Pharmaceutically acceptable counterions include chloro, bromo,iodo, trifluoroacetate and acetate. The counterion of choice can beintroduced using ion exchange resins.

It will be appreciated that the compounds described herein may havemetal binding, chelating, complex forming properties and therefore mayexist as metal complexes or metal chelates.

Some of the compounds described herein may also exist in theirtautomeric form.

A “therapeutically effective amount” of the disclosed compounds is adosage of the compound that is sufficient to achieve a desiredtherapeutic effect, such as inhibition of angiogenesis or an anti-tumoror anti-metastatic effect, inhibition of TNF-α activity, inhibition ofimmune cytokines, or treatment of a neurodegenerative disease. In someexamples, a therapeutically effective amount is an amount sufficient toachieve tissue concentrations at the site of action that are similar tothose that are shown to modulate angiogenesis, TNF-α activity, or immunecytokines, in tissue culture, in vitro, or in vivo. For example, atherapeutically effective amount of a compound may be such that thesubject receives a dosage of about 0.1 μg/kg body weight/day to about1000 mg/kg body weight/day, for example, a dosage of about 1 μg/kg bodyweight/day to about 1000 μg/kg body weight/day, such as a dosage ofabout 5 μg/kg body weight/day to about 500 μg/kg body weight/day.

The term “stereoisomer” refers to a molecule that is an enantiomer,diasteromer or geometric isomer of a molecule. Stereoisomers, unlikestructural isomers, do not differ with respect to the number and typesof atoms in the molecule's structure but with respect to the spatialarrangement of the molecule's atoms. Examples of stereoisomers includethe (+) and (−) forms of optically active molecules.

The term “modulate” refers to the ability of a disclosed compound toalter the amount, degree, or rate of a biological function, theprogression of a disease, or amelioration of a condition. For example,modulating can refer to the ability of a compound to elicit an increaseor decrease in angiogenesis, to inhibit TNF-α activity, or to inhibittumor metastasis or tumorigenesis.

The term “angiogenic activity” refers to the ability of a disclosedcompound or a particular concentration of a disclosed compound tostimulate angiogenesis. Angiogenic activity may be detected in vivo orin vitro. Angiogenic compounds or angiogenic concentrations of disclosedcompounds stimulate angiogenesis, and such compounds and/orconcentrations may be readily identified by those of ordinary skill inthe art, using, for example, the methods described in the Examples thatfollow.

The term “anti-angiogenic activity” refers to the ability of a compoundor a particular concentration of a disclosed compound to inhibitangiogenesis. Anti-angiogenic activity may be detected in vivo or invitro. Anti-angiogenic or anti-angiogenic concentrations of disclosedcompounds inhibit angiogenesis, and such compounds and/or concentrationsmay be readily identified by those of ordinary skill in the art, using,for example, the methods described in the Examples that follow.

“Treatment” refers to a therapeutic intervention that ameliorates a signor symptom of a disease or pathological condition after it has begun todevelop. As used herein, the term “ameliorating,” with reference to adisease or pathological condition, refers to any observable beneficialeffect of the treatment. The beneficial effect can be evidenced, forexample, by a delayed onset of clinical symptoms of the disease in asusceptible subject, a reduction in severity of some or all clinicalsymptoms of the disease, a slower progression of the disease, animprovement in the overall health or well-being of the subject, or byother parameters well known in the art that are specific to theparticular disease. The phrase “treating a disease” is inclusive ofinhibiting the full development of a disease or condition, for example,in a subject who is at risk for a disease, or who has a disease, such ascancer or a disease associated with a compromised immune system.“Preventing” a disease or condition refers to prophylactic administeringa composition to a subject who does not exhibit signs of a disease orexhibits only early signs for the purpose of decreasing the risk ofdeveloping a pathology or condition, or diminishing the severity of apathology or condition.

Prodrugs of the disclosed compounds also are contemplated herein. Aprodrug is an active or inactive compound that is modified chemicallythrough in vivo physiological action, such as hydrolysis, metabolism andthe like, into an active compound following administration of theprodrug to a subject. The term “prodrug” as used throughout this textmeans the pharmacologically acceptable derivatives such as esters,amides and phosphates, such that the resulting in vivo biotransformationproduct of the derivative is the active drug as defined in the compoundsdescribed herein. Prodrugs preferably have excellent aqueous solubility,increased bioavailability and are readily metabolized into the activeinhibitors in vivo. Prodrugs of a compounds described herein may beprepared by modifying functional groups present in the compound in sucha way that the modifications are cleaved, either by routine manipulationor in vivo, to the parent compound. The suitability and techniquesinvolved in making and using prodrugs are well known by those skilled inthe art. F or a general discussion of prodrugs involving esters seeSvensson and Tunek, Drug Metabolism Reviews 165 (1988) and Bundgaard,Design of Prodrugs, Elsevier (1985).

The term “prodrug” also is intended to include any covalently bondedcarriers that release an active parent drug of the present invention invivo when the prodrug is administered to a subject. Since prodrugs oftenhave enhanced properties relative to the active agent pharmaceutical,such as, solubility and bioavailability, the compounds disclosed hereincan be delivered in prodrug form. Thus, also contemplated are prodrugsof the presently disclosed compounds, methods of delivering prodrugs andcompositions containing such prodrugs. Prodrugs of the disclosedcompounds typically are prepared by modifying one or more functionalgroups present in the compound in such a way that the modifications arecleaved, either in routine manipulation or in vivo, to yield the parentcompound. Prodrugs include compounds having a phosphonate and/or aminogroup functionalized with any group that is cleaved in vivo to yield thecorresponding amino and/or phosphonate group, respectively. Examples ofprodrugs include, without limitation, compounds having an acylated aminogroup and/or a phosphonate ester or phosphonate amide group. Inparticular examples, a prodrug is a lower alkyl phosphonate ester, suchas an isopropyl phosphonate ester.

Protected derivatives of the disclosed compounds also are contemplated.A variety of suitable protecting groups for use with the disclosedcompounds are disclosed in Greene and Wuts, Protective Groups in OrganicSynthesis; 3rd Ed.; John Wiley & Sons, New York, 1999.

In general, protecting groups are removed under conditions which willnot affect the remaining portion of the molecule. These methods are wellknown in the art and include acid hydrolysis, hydrogenolysis and thelike. One preferred method involves the removal of an ester, such ascleavage of a phosphonate ester using Lewis acidic conditions, such asin TMS-Br mediated ester cleavage to yield the free phosphonate. Asecond preferred method involves removal of a protecting group, such asremoval of a benzyl group by hydrogenolysis utilizing palladium oncarbon in a suitable solvent system such as an alcohol, acetic acid, andthe like or mixtures thereof. A t-butoxy-based group, including t-butoxycarbonyl protecting groups can be removed utilizing an inorganic ororganic acid, such as HCl or trifluoroacetic acid, in a suitable solventsystem, such as water, dioxane and/or methylene chloride. Anotherexemplary protecting group, suitable for protecting amino and hydroxyfunctions amino is trityl. Other conventional protecting groups areknown and suitable protecting groups can be selected by those of skillin the art in consultation with Greene and Wuts, Protective Groups inOrganic Synthesis; 3rd Ed.; John Wiley & Sons, New York, 1999. When anamine is deprotected, the resulting salt can readily be neutralized toyield the free amine. Similarly, when an acid moiety, such as aphosphonic acid moiety is unveiled, the compound may be isolated as theacid compound or as a salt thereof.

Particular examples of the presently disclosed compounds include one ormore asymmetric centers; thus these compounds can exist in differentstereoisomeric forms. Accordingly, compounds and compositions may beprovided as individual pure enantiomers or as stereoisomeric mixtures,including racemic mixtures. In certain embodiments the compoundsdisclosed herein are synthesized in or are purified to be insubstantially enantiopure form, such as in a 90% enantiomeric excess, a95% enantiomeric excess, a 97% enantiomeric excess or even in greaterthan a 99% enantiomeric excess, such as in enantiopure form.

Groups which are substituted (e.g. substituted alkyl), may in someembodiments be substituted with a group which is substituted (e.g.substituted aryl). In some embodiments, the number of substituted groupslinked together is limited to two (e.g. substituted alkyl is substitutedwith substituted aryl, wherein the substituent present on the aryl isnot further substituted). In some embodiments, a substituted group isnot substituted with another substituted group (e.g. substituted alkylis substituted with unsubstituted aryl).

III. Overview of Particularly Disclosed Embodiments

Disclosed are compounds that modulate TNF-α activity and/orangiogenesis, and as such can be used to treat a wide variety ofpathological conditions that are linked to angiogenesis and/or TNF-αactivity. The disclosed compounds also inhibit inducible nitric oxidesynthase (iNOS) and proinflammatory cytokines such as IFN-γ, IL-2 andIL-17. Pharmaceutically acceptable salts, stereoisomers, and metabolitesof all of the disclosed compounds also are contemplated. In someembodiments, the compounds are lenalidomide or pomalidomide derivativesin which carbonyl groups in corresponding non-sulfur-containinglenalidomide or pomalidomide derivatives are replaced by one or morethiocarbonyl groups.

In one embodiment, the compounds, or pharmaceutically acceptable saltsor esters, thereof have a structure of:

wherein A, B and D are each O or S, provided that least one of A, B andD is S; and R¹-R⁸ are each independently hydrogen, hydroxyl, acyl,substituted acyl, acyloxy, substituted acyloxy, alkyl, substitutedalkyl, alkenyl, substituted alkenyl, alkynyl, substituted alkynyl,alkoxy, substituted alkoxy, aryl, substituted aryl, amino, substitutedamino, halogen, heterocycloalkyl, substituted heterocycloalkyl,heteroaryl, substituted heteroaryl, or a thio-containing group.

R¹ is preferably amino. In certain embodiments, R²-R⁸ are each hydrogen.In other embodiments, R⁸ is a heterocycloalkyl (particularly with N asthe heteroatom), substituted heterocycloalkyl (particularly with N asthe heteroatom), heteroaryl, substituted heteroaryl, or athio-containing group. In certain embodiments, at least two of A, B andD are sulfur. For example, A and B are sulfur; A and D are sulfur; or Band D are sulfur. In certain embodiments, A, B and D are all sulfur.

Illustrative compounds of formula I include:

In another embodiment, the compounds, or pharmaceutically acceptablesalts or esters, thereof have a structure of:

wherein A, B, D and E are each O or S, provided that least one of A, B,D and E is S; and R²-R⁴ and R⁶-R⁸ are each independently hydrogen,hydroxyl, acyl, substituted acyl, acyloxy, substituted acyloxy, alkyl,substituted alkyl, alkenyl, substituted alkenyl, alkynyl, substitutedalkynyl, alkoxy, substituted alkoxy, aryl, substituted aryl, amino,substituted amino, halogen, heterocycloalkyl, substitutedheterocycloalkyl, heteroaryl, substituted heteroaryl, or athio-containing group.

In certain embodiments, R²-R⁴ and R⁶-R⁸ are each hydrogen. In otherembodiments, R⁸ is a heterocycloalkyl (particularly with N as theheteroatom), substituted heterocycloalkyl (particularly with N as theheteroatom), heteroaryl, substituted heteroaryl, or a thio-containinggroup. In certain embodiments, at least two of A, B, D and E are sulfur.For example, A and B are sulfur; A and D are sulfur; B and D are sulfur;A and E are sulfur; B and E are sulfur; D and E are sulfur; A, B and Dare sulfur; A, B and E are sulfur; B, D and E are sulfur; A, D and E aresulfur; A, B and E are sulfur. In certain embodiments, A, B, D and E areall sulfur.

An illustrative compound of formula II is:

The compounds disclosed herein may be used for treating autoimmunediseases such as rheumatoid, immune and degenerative arthritis. Forexample, the compounds disclosed herein may be used to reduceneuroinflammation as a treatment strategy for neurodegenerativedisorders. Examples of neurodegenerative disorders include Alzheimer'sdisease, Parkinson's disease, head trauma, stroke, ALS, rheumatoidarthritis, immune arthritis, degenerative arthritis, HIV dementia,Huntington's disease, multiple sclerosis, cerebral amyloid, angiopathy,tauopathies, peripheral neuropathies, and macular degeneration. Thecompounds may be used to reduce chronic systemic and CNS inflammation,and as immunomodulatory agents. The compounds are small molecular weightlipophilic compounds with physicochemical properties to pass through theblood-brain barrier, thereby lowering the rate of synthesis of TNF-α.

In certain embodiments, the compounds disclosed herein may exhibit notoxicity or tolerable toxicity at dosages of up to 25 mg/daily, moreparticularly up to 50 mg/daily, and most particularly up to 75 mg/daily.

Still further, a method for modulating angiogenesis in a subject isdisclosed. The method includes administering to the subject atherapeutically effective amount of one or more of any of the disclosedcompounds. Examples of compounds useful for the method are shown above.In some embodiments, where an anti-angiogenic compound or ananti-angiogenic concentration of a compound is utilized, thetherapeutically effective amount of the compound can be administered toa subject with a tumor to achieve an anti-tumor effect, such asinhibition of tumorigenesis or tumor metastasis. In other embodiments,the therapeutically effective amount of the compound is administered toa subject with a pathological angiogenesis. Alternatively, wherestimulation of angiogenesis is desired an angiogenic compound or anangiogenic concentration of a compound is administered to a subject tostimulate angiogenesis.

As angiogenesis inhibitors, the disclosed compounds are useful in thetreatment of both primary and metastatic solid tumors, includingcarcinomas of breast, colon, rectum, lung, oropharynx, hypopharynx,esophagus, stomach, pancreas, liver, gallbladder and bile ducts, smallintestine, urinary tract (including kidney, bladder and urothelium),female genital tract, (including cervix, uterus, and ovaries as well aschoriocarcinoma and gestational trophoblastic disease), male genitaltract (including prostate, seminal vesicles, testes and germ celltumors), endocrine glands (including the thyroid, adrenal, and pituitaryglands), and skin, as well as hemangiomas, melanomas, sarcomas(including those arising from bone and soft tissues as well as Kaposi'ssarcoma) and tumors of the brain, nerves, eyes, and meninges (includingastrocytomas, gliomas, glioblastomas, retinoblastomas, neuromas,neuroblastomas, Schwannomas, and meningiomas). Such compounds may alsobe useful in treating solid tumors arising from hematopoieticmalignancies such as leukemias (i.e. chloromas, plasmacytomas and theplaques and tumors of mycosis fungoides and cutaneous T-celllymphoma/leukemia) as well as in the treatment of lymphomas (bothHodgkin's and non-Hodgkin's lymphomas). In addition, these compounds maybe useful in the prevention of metastases from the tumors describedabove either when used alone or in combination with radiotherapy and/orother chemotherapeutic agents. The compounds are also useful in treatingmultiple myeloma.

Such compounds can also be used to treat a pathological (i.e. abnormal,harmful or undesired) angiogenesis, for example, various ocular diseasessuch as diabetic retinopathy, retinopathy of prematurity, corneal graftrejection, retrolental fibroplasia, neovascular glaucoma, rubeosis,retinal neovascularization due to macular degeneration, hypoxia,angiogenesis in the eye associated with infection or surgicalintervention, and other abnormal neovascularization conditions of theeye; skin diseases such as psoriasis; blood vessel diseases such ashemagiomas, and capillary proliferation within atherosclerotic plaques;Osler-Webber Syndrome; myocardial angiogenesis; plaqueneovascularization; telangiectasia; hemophiliac joints; angiofibroma;and wound granulation. Other uses include the treatment of diseasescharacterized by excessive or abnormal stimulation of endothelial cells,including but not limited to intestinal adhesions, Crohn's disease,atherosclerosis, scleroderma, and hypertrophic scars, such as keloids.Another use is as a birth control agent, by inhibiting ovulation andestablishment of the placenta. The disclosed compounds are also usefulin the treatment of diseases that have angiogenesis as a pathologicconsequence such as cat scratch disease (Rochele minalia quintosa) andulcers (Helicobacter pylori). The disclosed compounds are also useful toreduce bleeding by administration prior to surgery, especially for thetreatment of resectable tumors.

Angiogenic compounds or angiogenic concentrations of disclosed compoundcan be used can be used to treat a variety of conditions that wouldbenefit from stimulation of angiogenesis, stimulation of vasculogenesis,increased blood flow, and/or increased vascularity. Particular examplesof conditions and diseases amenable to treatment using disclosedangiogenic compounds, or angiogenic concentrations of disclosedcompounds, include any condition associated with an obstruction of ablood vessel, such as obstruction of an artery, vein, or of a capillarysystem. Specific examples of such conditions or disease include, but arenot necessarily limited to, coronary occlusive disease, carotidocclusive disease, arterial occlusive disease, peripheral arterialdisease, atherosclerosis, myointimal hyperplasia (such as due tovascular surgery or balloon angioplasty or vascular stenting),thromboangiitis obliterans, thrombotic disorders, vasculitis, and thelike. Examples of conditions or diseases that may be prevented using thedisclosed angiogenic compounds/concentrations include, but are notlimited to, heart attack (myocardial infarction) or other vasculardeath, stroke, death or loss of limbs associated with decreased bloodflow, and the like. Other therapeutic uses for angiogenesis stimulationaccording to the disclosure include, but are not necessarily limited toaccelerating healing of wounds or ulcers; improving the vascularizationof skin grafts or reattached limbs so as to preserve their function andviability; improving the healing of surgical anastomoses (such as inre-connecting portions of the bowel after gastrointestinal surgery); andimproving the growth of skin or hair.

Yet further, a method for inhibiting TNF-α activity in a subject usingthe disclosed compounds is provided. The method includes administering atherapeutically effective amount of a disclosed compound to a subject toachieve a TNF-α inhibitory effect. The disclosed compounds having TNF-αinhibitory effects are useful for treating many inflammatory,infectious, immunological, and malignant diseases. These include but arenot limited to septic shock, sepsis, endotoxic shock, hemodynamic shockand sepsis syndrome, post ischemic reperfusion injury, malaria,mycobacterial infection, meningitis, psoriasis and other dermaldiseases, congestive heart failure, fibrotic disease, cachexia, graftrejection, cancer, tumor growth, undesirable angiogenesis, autoimmunedisease, opportunistic infections in AIDS, rheumatoid arthritis,rheumatoid spondylitis, osteoarthritis, other arthritic conditions,inflammatory bowel disease, Crohn's disease, ulcerative colitis,multiple sclerosis, systemic lupus erythrematosis, ENL in leprosy,radiation damage, and hyperoxic alveolar injury.

The disclosed compounds can be used in combination with othercompositions and procedures for the treatment of diseases. For example,a tumor can be treated conventionally with surgery, radiation orchemotherapy in combination with an anti-angiogeniccompound/concentration and then, optionally the compound/concentrationcan be further administered to the subject to extend the dormancy ofmicrometastases and to stabilize and inhibit the growth of any residualprimary tumor. Alternatively, an angiogenic compound or angiogenicconcentration of a compound can be used in combination with otherangiogenesis stimulating agents. For example, thermal energy (in theform of resistive heating, laser energy or both) to create thermallytreated stimulation zones or pockets (optionally interconnected, atleast initially, by small channels) in the tissue for the introductionof blood born growth and healing factors, along with stimulatedcapillary growth surrounding the thermally treated zones. Suchstimulation zones allow increased blood flow to previously ischemicand/or nonfunctional tissue (such as cardiac tissue) with a concomitantincreased supply of oxygen and nutrients ultimately resulting in arevitalization of the treated sections the tissue when used incombination with the angiogenic compositions/concentrations. In otherembodiments, disclosed compounds exhibiting TNF-α inhibitory activitycan be combined with other TNF-α inhibitory agents, for example,steroids such as dexamethasone and prednisolone. When used for treatmentof a cancer, the compounds can be used in combination withchemotherapeutic agents and/or radiation and/or surgery.

Examples of other chemotherapeutic agents that can be used incombination with the disclosed compounds include alkylating agents,antimetabolites, natural products, kinase inhibitors, hormones and theirantagonists, and miscellaneous other agents. Examples of alkylatingagents include nitrogen mustards (such as mechlorethamine,cyclophosphamide, melphalan, uracil mustard or chlorambucil), alkylsulfonates (such as busulfan), and nitrosoureas (such as carmustine,lomustine, semustine, streptozocin, or dacarbazine). Examples ofantimetabolites include folic acid analogs (such as methotrexate),pyrimidine analogs (such as 5-FU or cytarabine), and purine analogs,such as mercaptopurine or thioguanine. Examples of natural productsinclude vinca alkaloids (such as vinblastine, vincristine, orvindesine), epipodophyllotoxins (such as etoposide or teniposide),antibiotics (such as dactinomycin, daunorubicin, doxorubicin, bleomycin,plicamycin, or mitocycin C), and enzymes (such as L-asparaginase).Examples of kinase inhibitors include small molecule inhibitors (such asIressa, Tarceva, PKI-166, CI-1033, CGP-5923A, EKB-569, TAK165,GE-572016, CI-1033, SU5416, ZD4190, PTK787/ZK222584, CGP41251, CEP-5214,ZD6474, BIBF1000, VGA1102, SU6668, SU11248, CGP-57148, tricyclicquinoxalines, SU4984, SU5406, Gleevec, NSC680410, PD166326, PD1173952,CT53518, GTP14564, PKC412, PP1, PD116285, CGP77675, CGP76030, CEP-701,and CEP2583), ligand modulators (such as Bevacizumanb, MV833, SolubleFlt-1 and Flk-1, VEGF Trap, GFB 116, NM3, VEGF 121-diptheria toxinconjugate and Interfereon-α), and monoclonal antibodies againstreceptors (such as Cetuximab, ABX-EGF, Y10, MDX-447, h-R3, EMD 72000,herceptin, MDX-H210, pertuzumab, IMC-1C11, and MF1). Examples ofhormones and antagonists include adrenocorticosteroids (such asprednisone), progestins (such as hydroxyprogesterone caproate,medroxyprogesterone acetate, and magestrol acetate), estrogens (such asdiethylstilbestrol and ethinyl estradiol), antiestrogens (such astamoxifen), and androgens (such as testerone proprionate andfluoxymesterone). Examples of miscellaneous agents include platinumcoordination complexes (such as cis-diamine-dichloroplatinum II, whichis also known as cisplatin), substituted ureas (such as hydroxyurea),methyl hydrazine derivatives (such as procarbazine), vaccines (such asAPC8024), AP22408, B43-genistein conjugate, paclitaxel, AG538, andadrenocrotical suppressants (such as mitotane and aminoglutethimide). Inaddition, the disclosed compounds can be combined with gene therapyapproaches, such as those targeting VEGF/VEGFR (including antisenseoligonucleotide therapy, Adenovirus-based Flt-1 gene therapy,Retrovirus-base Flk-1 gene therapy, Retrovirus-based VHL gene therapy,and angiozyme) and IGF-1R (including INX-4437). Examples of the mostcommonly used chemotherapy drugs that can be used in combination withthe disclosed tricyclic compounds agent include Adriamycin, Alkeran,Ara-C, BiCNU, Busulfan, CCNU, Carboplatinum, Cisplatinum, Cytoxan,Daunorubicin, DTIC, 5-FU, Fludarabine, Hydrea, Idarubicin, Ifosfamide,Methotrexate, Mithramycin, Mitomycin, Mitoxantrone, Nitrogen Mustard,Taxol, Velban, Vincristine, VP-16, Gemcitabine (Gemzar), Herceptin,Irinotecan (Camptosar, CPT-11), Leustatin, Navelbine, Rituxan STI-571,Taxotere, Topotecan (Hycamtin), Xeloda (Capecitabine), Zevelin andcalcitriol.

The disclosed compounds also can be combined with radiotherapy employingradioisotopes (such as ³²P, ⁹⁰Y, ¹²⁵I, ¹³¹I, and ¹⁷⁷Lu), particle beams(such as proton, neutron and electron beams) and electromagneticradiation (such as gamma rays, x-rays and photodynamic therapy usingphotosensitizers and visible or ultraviolet rays).

Additionally, the disclosed compounds can be combined withpharmaceutically acceptable excipients, and optionally sustained-releasematrices, such as biodegradable polymers, to form therapeuticcompositions. Therefore, also disclosed are pharmaceutical compositionsincluding one or more of any of the compounds disclosed above and apharmaceutically acceptable carrier. The composition may comprise a unitdosage form of the composition, and may further comprise instructionsfor administering the composition to a subject to inhibit angiogenesis,for example, instructions for administering the composition to achievean anti-tumor effect or to inhibit a pathological angiogenesis. Suchpharmaceutical compositions may be used in methods for modulatingangiogenesis or TNF-α activity in a subject by administering to thesubject a therapeutically effective amount of the composition.

The disclosed pharmaceutical compositions can be in the form of tablets,capsules, powders, granules, lozenges, liquid or gel preparations, suchas oral, topical, or sterile parenteral solutions or suspensions (e.g.,eye or ear drops, throat or nasal sprays, etc.), transdermal patches,and other forms known in the art.

Pharmaceutical compositions can be administered systemically or locallyin any manner appropriate to the treatment of a given condition,including orally, parenterally, rectally, nasally, buccally, vaginally,topically, optically, by inhalation spray, or via an implantedreservoir. The term “parenterally” as used herein includes, but is notlimited to subcutaneous, intravenous, intramuscular, intrasternal,intrasynovial, intrathecal, intrahepatic, intralesional, andintracranial administration, for example, by injection or infusion. Fortreatment of the central nervous system, the pharmaceutical compositionsmay readily penetrate the blood-brain barrier when peripherally orintraventricularly administered.

Pharmaceutically acceptable carriers include, but are not limited to,ion exchangers, alumina, aluminum stearate, lecithin, serum proteins(such as human serum albumin), buffers (such as phosphates), glycine,sorbic acid, potassium sorbate, partial glyceride mixtures of saturatedvegetable fatty acids, water, salts or electrolytes such as protaminesulfate, disodium hydrogen phosphate, potassium hydrogen phosphate,sodium chloride, zinc salts, colloidal silica, magnesium trisilicate,polyvinyl pyrrolidone, cellulose-based substances, polyethylene glycol,sodium carboxymethylcellulose, polyacrylates, waxes,polyethylene-polyoxypropylene-block polymers, polyethylene glycol, andwool fat.

Tablets and capsules for oral administration can be in a form suitablefor unit dose presentation and can contain conventional pharmaceuticallyacceptable excipients. Examples of these include binding agents such assyrup, acacia, gelatin, sorbitol, tragacanth, and polyvinylpyrrolidone;fillers such as lactose, sugar, corn starch, calcium phosphate,sorbitol, or glycine; tableting lubricants, such as magnesium stearate,talc, polyethylene glycol, or silica; disintegrants, such as potatostarch; and dispersing or wetting agents, such as sodium lauryl sulfate.Oral liquid preparations can be in the form of, for example, aqueous oroily suspensions, solutions, emulsions, syrups or elixirs, or can bepresented as a dry product for reconstitution with water or othersuitable vehicle before use.

The pharmaceutical compositions can also be administered parenterally ina sterile aqueous or oleaginous medium. The composition can be dissolvedor suspended in a non-toxic parenterally-acceptable diluent or solvent,e.g., as a solution in 1,3-butanediol. Commonly used vehicles andsolvents include water, physiological saline, Hank's solution, Ringer'ssolution, and sterile, fixed oils, including synthetic mono- ordi-glycerides, etc. For topical application, the drug may be made upinto a solution, suspension, cream, lotion, or ointment in a suitableaqueous or non-aqueous vehicle. Additives may also be included, forexample, buffers such as sodium metabisulphite or disodium edeate;preservatives such as bactericidal and fungicidal agents, includingphenyl mercuric acetate or nitrate, benzalkonium chloride orchlorhexidine, and thickening agents, such as hypromellose.

The dosage unit involved depends, for example, on the condition treated,nature of the formulation, nature of the condition, embodiment of theclaimed pharmaceutical compositions, mode of administration, andcondition and weight of the patient. Dosage levels are typicallysufficient to achieve a tissue concentration at the site of action thatis at least the same as a concentration that has been shown to be activein vitro, in vivo, or in tissue culture. For example, a dosage of about0.1 μg/kg body weight/day to about 1000 mg/kg body weight/day, forexample, a dosage of about 1 μg/kg body weight/day to about 1000 μg/kgbody weight/day, such as a dosage of about 5 μg/kg body weight/day toabout 500 μg/kg body weight/day can be useful for treatment of aparticular condition.

The compounds can be used in the form of pharmaceutically acceptablesalts derived from inorganic or organic acids and bases, including, butnot limited to: acetate, adipate, alginate, aspartate, benzoate,benzenesulfonate, bisulfate, butyrate, citrate, camphorate,camphorsulfonate, cyclopentanepropionate, digluconate, dodecylsulfate,ethanesulfonate, fumarate, glucoheptanoate, glycerophosphate,hemisulfate, heptanoate, hexanoate, hydrochloride, hydrobromide,hydroiodide, 2-hydroxyethanesulfonate, lactate, maleate,methanesulfonate, 2-naphthalenesulfonate, nicotinate, oxalate, pamoate,pectinate, persulfate, 3-phenylpropionate, picrate, pivalate,propionate, succinate, tartrate, thiocyanate, tosylate, and undecanoate.Base salts include, but are not limited to, ammonium salts, alkali metalsalts (such as sodium and potassium salts), alkaline earth metal salts(such as calcium and magnesium salts), salts with organic bases (such asdicyclohexylamine salts), N-methyl-D-glucamine, and salts with aminoacids (such as arginine, lysine, etc.). Basic nitrogen-containing groupscan be quaternized, for example, with such agents as C1-8 alkyl halides(such as methyl, ethyl, propyl, and butyl chlorides, bromides, andiodides), dialkyl sulfates (such as dimethyl, diethyl, dibutyl, andiamyl sulfates), long-chain halides (such as decyl, lauryl, myristyl,and stearyl chlorides, bromides, and iodides), aralkyl halides (such asbenzyl and phenethyl bromides), etc. Water or oil-soluble or dispersibleproducts are produced thereby.

EXAMPLES—COMPOUND SYNTHESIS I. Synthesis of 1,6′-Dithiolenalidomide 1.Methyl 2-bromomethyl-3-nitrobenzoate (2)

A mixture of methyl 2-methyl-3-nitrobenzoate (1) (18.7 g, 95.8 mmol),N-bromosuccinimide (17.1 g, 96.1 mmol) and benzoyl peroxide (0.7 g, 2.9mmol) in carbon tetrachloride (500 mL) was refluxed for 20 h. Thereaction mixture was cooled and concentrated. Thereafter, it wasprecipitated and washed by ethyl ether to afford product (2) (22.3 g,84.8%) as yellowish crystals: mp 68.0-70.0° C. (ref. 67-70° C.).

2. 2-(2, 6-Dioxopiperidine-3-yl)-4-nitrophthalimidine (3)

A mixture of methyl 2-bromomethyl-3-nitrobenzoate (2) (3.5 g, 12.8mmol), (2, 6-dioxopiperidine-3-yl)amine trifluoroacetate (3.1 g, 12.8mmol) and potassium carbonate (3.6 g, 26.0 mmol) inN,N-dimethylacetamide (DMA) (12.5 mL) was stirred for 24.0 h under anitrogen atmosphere at room temperature, and then continuously reactedfor 16.5 h at 50° C. After removing solvent, the residues were washedwith water and methanol to afford product (3) (2.7 g, 73.0%) asyellowish crystals: mp 274.0-276.0° C.; ¹H NMR (DMSO-d₆) δ 11.09 (s, 1H,NH), 8.48 (d, J=7.2 Hz, 1H, C7-H), 8.19 (d, J=7.2 Hz, 1H, C5-H), 7.83(t, J=7.2 Hz, 1H, C6-H), 5.27-5.14 (m, 1H, C3′-H), 4.91 and 4.78 (ABsystem, J=8.0 Hz, 2H, C3-H), 3.00-2.82 (m, 1H, C5′-H), 2.63-2.44 (m, 2H,C5′-H, C4′-H) and 2.09-1.98 (m, 1H, C4′-H) ppm; ¹³C NMR (DMSO-d₆) δ174.7, 172.6, 167.8, 145.3, 139.3, 136.6, 132.1, 131.5, 128.9, 53.7,50.3, 33.1 and 24.1 ppm; MS (CI/CH₄), m/z 290 (MH⁺).

3. 4-Nitro-1-thioxo-2-(2-oxo-6-thioxopiperidine-3-yl)phthalimidine (4)

A mixture of 2-(2, 6-dioxopiperidine-3-yl)-4-nitrophthalimidine (3) (1.3g, 4.6 mmol) and Lawesson's reagent (3.0, 7.4 mmol) in toluene (900 mL)was refluxed under an atmosphere of nitrogen for 26.0 h. The crudeproduct was purified by column chromatography using EtOAc:petroleumether (1:2) as the eluent to afford compound (4) (1.3 g, 85.8%) asyellow needle crystals: mp 250.0-251.0° C.; ¹H NMR (DMSO-d₆) δ 12.40 (s,1H, NH), 8.47 (d, J=6.3 Hz, 1H, C5-H), 8.28 (d, J=6.3 Hz, 1H, C7-H),7.81 (t, J=6.3 Hz, 1H, C6-H), 5.96 (d, J=12.5 Hz, 1H, C3′-H), 5.25 and5.15 (AB system, J=21.6 Hz, 2H, C3-H), 3.31-3.13 (m, 2H), 2.81-2.61 (m,1H) and 2.11-1.99 (m, 1H) ppm; ¹³C NMR (DMSO-d₆) δ 210.5, 191.2, 166.9,143.5, 141.5, 136.6, 131.6, 130.7, 127.3, 56.8, 56.4, 41.2 and 23.5 ppm;MS (CI/CH₄), m/z 322 (MH⁺); Anal. Calcd for C₁₃H₁₁N₃O₃S₂: C, 48.58; H,3.45; N, 13.08. Found: C, 48.89; H, 3.60; N, 12.67.

4. 1,6′-Dithiolenalidomide (5)

A mixture of4-nitro-1-thioxo-2-(2-oxo-6-thioxopiperidine-3-yl)phthalimidine (4)(132.0 mg, 0.4 mmol) and palladium on activated carbon (10 wt. %, 230mg) in methanol (250.0 mL) was shaken under an atmosphere of hydrogen(44 lbs) at room temperature for 69.0 h. Thereafter, the catalyst wasfiltered through Celite and the filtrate was concentrated by rotaryevaporator. The residue was purified by chromatography usingCH₂Cl₂:methanol (10:1) as the eluent to afford compound (5) (61.3 mg,52.6%) as a yellow gum: ¹H NMR (DMSO-d₆) δ 12.63 (s, 1H, NH), 7.20 (t,J=7.8 Hz, 1H, C6-H), 7.09 (d, J=7.5 Hz, 1H, C7-H), 6.81 (d, J=7.8 Hz,1H, C5-H), 5.97 (s, br, 1H, C3′-H), 5.45 (s, 2H, NH₂), 4.53 and 4.47 (ABsystem, J=19.8 Hz, 2H, C3-H), 3.30-2.51 (m, 2H), 2.44-2.05 (m, 2H) ppm;¹³C NMR (DMSO-d₆) δ 210.4, 194.8, 167.5, 143.4, 139.8, 129.4, 124.7,117.0, 113.0, 55.9, 53.4, 41.1 and 24.0 ppm; MS (CI/CH₄), m/z 292 (MH⁺).

II. Synthesis of Dithiopomalidomide 1. 2-(2,6-Dioxopiperidine-3-yl)-4-nitrophthalimide (7)

A mixture of 3-nitrophthalic anhydride (6) (1.5 g, 7.8 mmol) and (2,6-dioxopiperidine-3-yl)amine trifluoroacetate (1.9 g, 7.8 mmol) inacetic acid (60.0 mL) was refluxed for 4.5 h under a nitrogenatmosphere. After removing solvent, the residues were recrystallizedwith ethyl acetate to afford product (7) (1.8 g, 75.0%) as a purplishsolid.

2. 4-Nitro-1-thioxo-2-(2-oxo-6-thioxopiperidine-3-yl)phthalimide (8)

A mixture of 2-(2, 6-dioxopiperidine-3-yl)-4-nitrophthalimide (7) andLawesson's reagent in toluene was refluxed under an atmosphere ofnitrogen for 26.0 h. The crude product was purified by columnchromatography using EtOAc:petroleum ether as the eluent to affordcompound (8).

3. Pomalidomide (9)

A mixture of 2-(2, 6-dioxopiperidine-3-yl)-4-nitrophthalimide (7) (66.0mg, 0.2 mmol) and palladium on activated carbon (10 wt. %, 45.0 mg) inmethanol (80.0 mL) was shaken under an atmosphere of hydrogen (44 lbs)at room temperature for 7.0 h. Thereafter, the catalyst was filteredthrough Celite and the filtrate was concentrated by rotary evaporator.The residue was purified by chromatography using CH₂Cl₂:methanol as theeluent to afford compound (9).

4. Dithiopomalidomide (10)

A mixture of4-nitro-1-thioxo-2-(2-oxo-6-thioxopiperidine-3-yl)phthalimide (8) andpalladium on activated carbon (10 wt. %) in methanol was shaken under anatmosphere of hydrogen (44 lbs) at room temperature. Thereafter, thecatalyst was filtered through Celite and the filtrate was concentratedby rotary evaporator. The residue was purified by chromatography usingCH₂Cl₂:methanol as the eluent to afford compound (10).

Examples—Toxicity and TNF-α Inhibition

In the examples below the dithiolenalidomide is 1,6′-Dithiolenalidomidehaving a structure of:

The dithiothalidomide is 3,6′-Dithiothalidomide having a structure of:

ProceduresCellular Toxicity—Lactate Dehydrogenase Assay

To assess for potential toxicological effects of drugs on cells, a LDHassay was performed on conditioned media samples from control andtreated cells. This assay provides a measure of the functional integrityof the NB cell membrane. The assay was carried out as recommended by themanufacturer, Sigma-Aldrich (St Louis, Mo.), and is based on thepresence of released, cellular LDH in the culture media. The presence ofLDH allows for the conversion of NAD into NADH, which then causes acolor reaction of a tetrazolium dye substrate. The colored product ofthe transformed tetrazolium dye can be measured spectrophotometricallyat 490 nm. Optical densities (O.D.) were determined at a wavelength of490 nm at hourly intervals for 3 to 4 hr.

Cellular Proliferation—MTS Assay

The CellTiter 96 AQueous One Solution Cell Proliferation Assay (Promega,Madison, Wis.) is routinely used as an assay of cell proliferation, andwas used herein, according to the manufacturer's recommendations.Changes in cellular health status are determined by use of indirectmeasures related to the formation of a colored tetrazolium dye productthat can be measured spectrophotometrically at 490 nm A. An elevation inabsorbance is indicative of an increase in cell number and, hence,cellular proliferation. Optical densities were measured after 1 to 2hours incubation and were expressed as a % change from their appropriatecontrol.

Nitrite Levels—Griess Reagent System Assay

Nitrite levels in the culture media were measured by use of the GriessReagent System (Promega, Madison, Wis.), following the manufacturer'sprotocol. The O.D. of unknown samples was read at 520 nm A, compared toa sodium nitrite standard curve (1.5 μM to 100 μM) and nitrite measuredmedia concentrations expressed as a % change from their appropriatecontrol.

TNF-α Protein Assay

TNF-α protein levels were measured by use of an ELISA specific for mouseTNF-α protein (BioLegend, San Diego, Calif.), O.D.s measured at 450 nmλ, obtained from the unknown samples were compared to a TNF-α proteinstandard curve (7.8 to 500 pg/ml) and the calculated TNF-α levels areexpressed as a % change from their appropriate control or as pg/ml.

Results

The results indicate that dithiolenalidomide is unexpectedly less toxiccompared to dithiothalidomide, particularly at drug concentrations or 10μm or greater. However, dithiolenalidomide surprisingly retained TNF-αinhibitory effect despites its lower toxicity.

In particular, data obtained from the lactate dehydrogenase assaycomparing 3,6′-dithiothalidomide with the DMSO control, indicate therewas evidence of cellular stress as illustrated by elevated O.D. valuesat time points from 60 min after the addition of LPS (see FIG. 1). TheO.D. values for dithiolenalidomide treatment measured at the same time,showed no evidence of cellular stress in the RAW 264.7 cells in a LDHAssay.

Both 3,6′-dithiothalidomide and dithiolenalidomide treatment reduced thelevels of TNF-α protein detected in the LPS stimulated RAW 264.7 cellculture media when compared with the DMSO control (see FIG. 2).

Comparing 3,6′-dithiothalidomide (20 μM) with the DMSO control,indicates that there was evidence of cellular stress in the LPSstimulated RAW 264.7 cells in an MTS assay (see FIG. 3). The cellularhealth for 3,6′-dithiothalidomide displayed a reduction from the 100%control values (see FIG. 3). However, dithiolenalidomide, atconcentrations that far exceed 20 μM, failed to induce any cellularstress in the LPS stimulated RAW 264.7 cells (see FIG. 3).

The levels of a marker of nitric oxide mediated oxidative stress, namelynitrite were measured in cell culture media. Both 3,6′-dithiothalidomideand dithiolenalidomide reduced the levels of nitrite in LPS stimulatedRAW 264.7 media, however treatment of cells with 3,6′-dithiothalidomidewas associated with cellular stress while those treated withdithiolenalidomide failed to show any associated cell stress (see FIG.3).

The levels of TNF-α protein were measured in cell culture media. As whatwas observed with nitrite measurements, both 3,6′-dithiothalidomide anddithiolenalidomide reduced the levels of TNF-α protein in LPS stimulatedRAW 264.7 media, however cells treated with 3,6′-dithiothalidomidedisplayed some cell stress while those treated with dithiolenalidomidefailed to show any associated cell stress (see FIG. 3).

Neither thalidomide and lenalidomide treatment induced any cell stressas indicated by changes in O.D. values of the MTS assay (see FIG. 4).

Examples—Inhibition of Immune Cytokines

The capacity of several different compounds to alter the generation ofthree distinct immune cytokines by TCR-stimulated T cells of young andold subjects was investigated. In initial studies designed to define thedose-range, lenalidomide enhanced generation of IFN-γ by TCR-stimulatedT cells of two young and two old healthy subjects significantly atconcentrations of 0.03 μM to 3 μM up to a peak of nearly three-fold at 3μM (FIG. 5A). Significant inhibition of generation of IFN-γ was observedinstead for dithiolenalidomide beginning at 1 μM and dithiothalidomidebeginning at 3 μM, with only modest inhibition by thalidomide at 100 μM.For stimulated T cell generation of IL-2, again only lenalidomideenhanced the levels significantly at concentrations of 0.03 μM to 30 μM,with mean maximal enhancement of 9.5-fold at 1 μM in this mixed group ofyoung and old subjects (FIG. 5B). Significant inhibition of IL-2generation was found for dithiolenalidomide beginning at 3 μM and fordithiothalidomide starting at 30 μM, whereas thalidomide had nodetectable effect at up to 100 μM. The distinctively high level ofvariation of lenalidomide enhancement of IL-2 generation suggested thatthere may be differences in the effects of lenalidomide on T cells ofyoung and old subjects.

No compound was capable of enhancing TCR-stimulated T cell generation ofIL-17. However, there was significant inhibition of generation of IL-17by dithiolenalidomide at 0.1 μM and higher, lenalidomide at 0.3 μM andhigher, dithiothalidomide at 3 μM and higher, and thalidomide only at100 μM (FIG. 5C). None of the thalidomide-type drugs altered cytokinegeneration alone in the absence of TCR-directed stimulation (data notshown).

In view of the many possible embodiments to which the principles of thedisclosed compounds, compositions and methods may be applied, it shouldbe recognized that the illustrated embodiments are only preferredexamples should not be taken as limiting the scope of the invention.

What is claimed is:
 1. A method for treating a neurodegenerativedisorder in a subject, comprising administering to the subject atherapeutically effective amount of a compound, or a pharmaceuticallyacceptable salt thereof, having a structure of: (i)

wherein A, B, D and E are each oxygen or sulfur, and R²-R⁴ and R⁶-R⁸ areeach independently hydrogen, hydroxyl, acyl, substituted acyl, acyloxy,substituted acyloxy, alkyl, substituted alkyl, alkenyl, substitutedalkenyl, alkynyl, substituted alkynyl, alkoxy, substituted alkoxy, aryl,substituted aryl, amino, substituted amino, halogen, heterocycloalkyl,substituted heterocycloalkyl, heteroaryl, substituted heteroaryl, or athio-containing group, provided that A and B are sulfur, and D and E areoxygen, or A and D are sulfur, and B and E are oxygen, or B and E aresulfur, and A and D are oxygen, or D and E are sulfur, and A and B areoxygen; or (ii)

and wherein the neurodegenerative disorder is Alzheimer's disease, headtrauma, stroke, Huntington's disease, or multiple sclerosis.
 2. Themethod of claim 1, wherein each of R²-R⁴ and R⁶-R⁸ is hydrogen.
 3. Themethod of claim 1, wherein the compound is:

or a pharmaceutically acceptable salt thereof.
 4. The method of claim 1,wherein the compound is:

or a pharmaceutically acceptable salt thereof.